Nitrite Toxicity to Danio Rerio: Effects of Fish Age and Chloride Concentrations

Abstract

Vosláfiová E., V. Pi‰tûková, Z. Svobodová: Nitrite Toxicity to Danio Rerio: Effects of Fish Age and Chloride Concentrations. Acta Vet. Brno 2006, 75: 107-113.The aim of the present study was to compare the acute nitrite toxicity for Danio rerio at the age of 20 -25 days (larval stage) and 2 -3 months (juvenile stage) at various chloride concentrations. The semistatic method according to OECD 203 was used in the tests. Nitrite (NO 2 -) is a naturally occurring anion in fresh and saline waters, its concentration in oxygenated waters is typically less than 0.005 mg·l -1 (Lewis and Morris 1986). Elevated concentration of nitrite can be found in water receiving nitrogenous effluents, in various hypoxic environments or in effluents from industries producing metal, dyes, and celluloid (Pitter 1999). The increased nitrite concentrations in water also present one of the frequent problems encountered both in aquaria and on fish farms. Sources of nitrites are mainly products of fish metabolism and decaying remains of food and faeces. In aquaria, fish are most frequently poisoned by nitrites that accumulate in the tank as a result of insufficient efficiency of biological filters (Adamsson et al. 1998;Etscheidt 2003; Dvofiák 2004;Svobodová et al. 2005a). An elevated ambient nitrite concentration is a potential problem for freshwater fish, since nitrite is actively taken up across the gills in competition with chloride (Maetz 1971;Williams and Eddy 1986;Jensen 2003).Nitrite toxicity to fish varies considerably and depends on a large number of external and internal factors whose importance is continuously verified and re-assessed. One of the important factors influencing nitrite toxicity for fish is the fish size and age. Lewis and Morris (1986) stated that small fish, even larvae, are unlikely to be more sensitive to nitrite than larger fish of the same species, and that there is definite evidence for some species that very small fish are less vulnerable to toxicity than fish of intermediate or large size. A study by Perrone and Meade (1977) indicated that coho salmon (Oncorhynchus kisutch) fry have greater tolerance to nitrite than coho yearlings. This phenomenon has been also observed in other species of salmonids. An early study by Smith and W illiams (1974) on rainbow trout (Salmo gairdneri) showed that small fish were less sensitive to 24h exposures of nitrite than larger ones. Russo et al. (1974) showed that rainbow trout larvae were slightly less susceptible to nitrite than larger fish and subsequent studies by Russo and ACTA VET. BRNO 2006, 75: 107-113

Nitrite Toxicity to Danio rerio: Effects of Subchronic Exposure on Fish Growth

“…In our trial we focused only on the influence of nitrite on fish growth. In previous experiments 96hLC50 values of NO 2 -were determined in juvenile zebrafish (Voslářová et al 2006). The acute NO 2 -toxicity to D. rerio aged 20-25 days as expressed by the 96hLC50 was 386.00 ± 29.75 mg·l -1 .…”

“…Acute toxicity of nitrite has been investigated and described in a number of fish species (Bowser et al 1983;Crawford and Allen 1977;Russo and Thurston 1977;McConnell 1985;Lewis and Morris 1986;Kroupová et al 2005;Pištěková et al 2005;Kroupová et al 2006;Voslářová et al 2006), but the effects of chronic nitrite exposure on their survival and growth have not been well documented yet. However, detailed knowledge of the impact of water quality factors on fundamental production characteristics such as growth performance, food conversion efficiency, and animal welfare is needed in order to effectively exploit the benefits of aquacultural systems (Siikavuopio and Saether 2006).…”

Nitrite toxicity assessment in Danio rerio and Poecilia reticulata

“…Wang et al (2006) (Voslářová et al 2006) or in chinook salmon (Oncorhynchus tshawytscha) (Crawford and Allen 1977). Svobodová et al (2005) have suggested some measures that should be done to prevent nitrite poisoning in fish.…”

“…The toxicity of nitrites for fish differs in dependence of many internal and external factors such as water quality, fish species, their size and individual sensitivity (Lewis and Morris 1986;Jensen 2003;Voslářová et al 2006). The most important factor influencing nitrite toxicity is the concentration of chloride ions in water.…”

“…The most important factor influencing nitrite toxicity is the concentration of chloride ions in water. Many authors proved in their studies the protective impact of chloride ions against intoxication of nitrites (Crawford and Allen 1977;Lewis and Morris 1986;Pištěková et al 2005;Voslářová et al 2006;Wang et al 2006;Weirich and Riche 2006).…”